1. Field of the Invention
The present invention relates generally to integrated circuits, and more specifically to a structure for utilizing a portion of an integrated circuit memory die.
2. Description of the Prior Art
During the manufacture of integrated circuit die, die are often discarded because a portion of the die is defective and can not be repaired at, for instance, laser repair. Even though a major portion of the die may be fully functional, it is often necessary to discard the entire die as scrap because the functional portion of the die is not recoverable. For instance, it is not uncommon to scrap a 64 K SRAM die which is partially functional and could yield a 16 K SRAM. Even though the 64 K SRAM could be used as a smaller 16 K SRAM device, it must be scrapped if there is no plausible method to recover the functional portion.
Another concern with using partially functional die as effectively smaller die is whether the die will fit into a package designed for a smaller die. Further, even if the die does fit, there is also concern that the package pinout may not accommodate the signal mapping of the die. For instance, pin number 27 on a 28 pin DIP package for a typical 64 K SRAM may be the Write Enable pin. However, the equivalent pin on a 16 K SRAM may be an Address pin. Specifically, some 16 K SRAM packages would have a pin other than pin 23 as the equivalent Address pin on a 24 pin DIP. If the 64 K SRAM die is fitted into the package of the 16 K SRAM, there will be mapping problems, because the Write Enable signal of the die is mapped to an Address pin on the 16 K SRAM package.